Tire/Rim Size

Zack1965 · 01-12-2013, 12:12 PM

Hi,
I just recently aquired a 1997 E 350 XL with a Quiggley conversion which was a retired ENG van for a news station in Denver. My plan is to slowly create a functional fun machine. It has what I assume to be stock steel rims on it...and crappy tires! The first order of business is to replace tires, and while at it, I would like to consider upgrading the rims.
I have read quite thoroughly throughout this forum...and I still don't fully understand what I might have. Through online info...the stock bolt pattern for that year was 8x6.5(8x165) with a 16x 8 rim. Is this still true after the conversion? If so...other than going to Discount Tire, or someplace simular, how can I find out what the largest tire I can put on the stock rim? From photos of projects here...it seems like 285/75 R16 should do quite well. Possibly, 305/70 R16's? When the conversation turns to "offset", etc...I am totally lost!
I would appreciate any insight or suggestions to help me along.

Thanks,
Steve.

rockbender · 01-14-2013, 04:38 PM

A 16x8 wheel will take the 285/75R16 just fine, and it will also fit the 305. As far as your rig goes, it would be best to mount up the tires you are potentially looking at and turn the wheel lock to lock and make sure you aren't getting into any control arms or sway bars. What size tires do you have now? Someone with a Quigley can hopefully share more info, but it seems that 265/75R16 was a pretty common size with the conversion, but I think you can run up to 285's without trouble.

shenrie · 01-14-2013, 10:14 PM

im running 285/75/16 tires on my 03 quigley, but i cant honestly tell you rim width or offset as i havent had a wheel off yet.

some quick info on offset and backspacing:

Quote:

1. Wheel Diameter. This is the diameter of the wheel. Stock wheels are commonly 15 or 16 inch diameter. This dimension is usually in 1 increments (i.e. 15, 16, 17) but some manufacturers offer 16.5, which is rare.

2. Wheel Width. This is the width of the wheel, measured inside the outer lip of the wheel. This dimension is usually in 1/2 increments (i.e. 7.5, 8)

3. Wheel Center.?This is the center of the wheel in relation to the width.

4. Offset. The distance from the centerline of the wheel to the face of the mounting surface of the wheel that contacts the hub.

4.1 Zero Offset. Indicates the mounting surface is at the wheel center.

4.2. Negative Offset.? Indicates the mounting?surface is behind (or inboard) the centerline of the rim. This is often found on standard rear-wheel-drive vehicles and on so-called reversed rims. (Diagram below shows negative offset)

4.3 Positive Offset. Indicates the mounting?surface is?in front of?(or outboard) the centerline of the rim. This is often found on front-wheel-drive vehicles.

5. Backspacing. The distance from the mounting surface to the inside?lip of the?wheel. This measurement is closely related to offset (without actually measuring, backspacing is about equal to [Wheel Width / 2] + [Offset] + [about 1/4] ).

6. Centerbore. The centerbore of a wheel is the size of the machined hole on the back of the wheel that centers the wheel properly on the hub of the car. This hole is machined to exactly match the hub so the wheels are precisely positioned, minimizing the chance of a vibration. This measurement may be critical to clear the hubs of a 4WD.

7. Bolt Circle. Also known as PCD (Pattern Circle Diameter). The bolt circle represents the diameter of an imaginary circle that goes through the center of the bolt holes

Zack1965 · 01-15-2013, 10:20 PM

Thanks for the info...
I have 245/75 R16 now...and they are a bit small compared to the wheel well! I did determine I have a 8 on 6.5 bolt pattern, and after rolling a 265/75 and a 285/75 up against the van, I thought the 265/75 was the way to go. Although...the 285's looked pretty good!
Good point on the turning to lock position to check for clearance...I will do that before all four are mounted.
Thanks for the info on the offset...I read some material on it and didn't grasp the full concept...but, pictures do help considerably.
Strange how on Craigs List there are numerous tires and rims available that people have pulled to replace with custom rims and tires...but, all are 8 on 170 bolt pattern.
Will just have to be patient!
Thanks again...

rockbender · 01-16-2013, 09:52 AM

Yes - be patient. That stuff comes up on CL all the time. Also, in case you didn't know, 8 lug Chevy and Dodge wheels are 8 on 6.5 as well. It is only the Ford Super Duty that went to the 8 on 170.

For reference, your tire heights are roughly as follows:
245's: 30.5"
265's: 31.6"
285's: 32.8"

The bigger/wider tires will also decrease fuel mileage (as a general rule) and affect final gear ratio as well.